A similar device is known from German Patent DE-OS 29 11 958. Herein the readily compressed bale is wrapped with a jacket in the shape of a polyethylene foil. This is effected by means of a complicated pivoting lever, which grips sideways around the bale and carries a coil with the jacket foil. The free foil end is held on the opposite side with a swivelable toe dog. The arrangement is mounted movably on a slide and is moved toward the bale in order to envelope it, simultaneously the pivoting lever makes a closing movement.
The known arrangement has a disadvantage as it is not completely automatic. The device has to be backed up from the wrapped bale with the pivoting lever opened once the wrapping is completed. Only after that, can the free end of the coil be connected to the toe dog again. The publication does not point out how this could be handled automatically. It is also disadvantageous that the jacket cannot be wrapped around the bale without wrinkles and that its tension over the width of the bale varies. This definitely requires the use of elastic, stretchable foils, which are not the optimal material for bale wrapping. In addition, the wrapped bales can only be hoop-cased once the wrapping device has moved back into its original position. Therefore the hoop-casing has to be an additional step. With regard to the resulting space requirements the realization of this wrapping device in a final compression station and its restricting supporting construction is more than questionable. All in all the known design is very complex, the operational safety is insufficient and the operation time ratio is unfavorable.
German Patent DE-OS 29 48 237 describes a bale compression device wherein the wrapping and the hoop-casing have to take place in separate stations outside the compression station. A movable foil carrier with two coils is provided for the wrapping of the bale. It wraps the jacket foil around the bale in a U-shape. For this purpose an additional and very complicated dolly and pressure ram system is required, by means of which the bale is held on a carousel table and turned from station to station on it. This arrangement cannot be realized with compression devices working with high pressure without a major density loss. Furthermore, this arrangement is also very complex and requires a long cycle time due to the use of different stations.